Eigenfactor provides two metrics:
- Eigenfactor: measure of the journal’s total importance to the scientific community
- Article Influence: measure of the average influence of each of a journal’s articles over the first five years after publication
Eigenfactor is freely available and is run by a group at the University of Washington.
They say, “Under an agreement with Thomson-Reuters, we are able to bring you the Eigenfactor metrics here at Eigenfactor.org free of charge. Scores will appear here annually, six months after they are released in the Thomson-Reuters Journal Citation Reports.”